IETF Transparent Interconnect of Lots of Links (“TRILL”) provides an architecture of Layer 2 control and forwarding that provides benefits such as pair-wise optimal forwarding, loop mitigation, multipathing and provisioning free. The TRILL protocol is described in detail in Perlman et al., “RBridges: Base Protocol Specification,” available at http://tools.ietf.org/html/draft-ietf-trill-rbridge-protocol-16. The TRILL base protocol supports approximately four-thousand customer (or tenant) identifications through the use of inner virtual local area network (“VLAN”) tags. The number of tenant identifications provided by the TRILL base protocol is insufficient for large multi-tenant data center deployments. Thus, a fine-grained labeling (“FGL”) networking scheme has been proposed to increase the number of tenant identifications to approximately sixteen million through the use of two inner VLAN tags. The FGL networking scheme is described in detail in Eastlake et al., “TRILL: Fine-Grained Labeling,” available at http://tools.ietf.org/html/draft-ietf-trill-fine-labeling-01.
Virtual extensible local area network (“VxLAN”) is a networking scheme that provides a Layer 2 overlay on top of Layer 3 network infrastructure. Similar to FGL, VxLAN supports approximately sixteen million tenant identifications. Specifically, according to VxLAN, customer frames are encapsulated with a VxLAN header containing a VxLAN segment ID/VxLAN network identifier (“VNI”), which is a 24-bit field to identify virtual Layer 2 networks for different tenants. The VxLAN networking scheme is discussed in detail in Mahalingham et al., “VXLAN: A Framework for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks,” available at http://tools.ietf.org/html/draft-mahalingam-dutt-dcops-vxlan-01.
As two complementary network virtualization schemes, TRILL FGL and VxLAN can co-exist in a multi-tenant data center. To facilitate their interworking, VxLAN origination and termination capabilities can be built into application-specific integrated circuits (“ASICs”) already supporting TRILL. In other words, packet-switching devices can be built with VxLAN gateway functionality. A VxLAN gateway can be configured to push FGL frames into VxLAN tunnels, as well as decapsulate frames from VxLAN tunnels for further forwarding as FGL frames. Accordingly, traffic can flow over the same physical network either natively in FGL or overlay in VxLAN.